Mice without a functional relaxin gene are unable to deliver milk to their pups.

We have used gene targeting to generate relaxin (rlx)-deficient mice. The majority (15 of 17) of homozygous (rlx-/-) mice are fertile and produce normal litters. However their mammary development is deficient; pups are unable to suckle and die within 24 h of birth unless cross-fostered to a wild-type (rlx+/+) foster mother. The nipples of rlx-/- animals do not enlarge significantly during pregnancy, and their histology retains the appearance of the virgin state. Breast parenchyma is somewhat underdeveloped at term even though milk is produced. Mammary ducts become grossly dilated in these animals. Heterozygous (rlx+/-) mice lactate normally. The interpubic ligament does not relax during pregnancy in rlx-/- mice. Plasma osmolality during late gestation was significantly higher (P < 0.001) in rlx-/- mice than in wild-type controls.

Sensory nerve endings in the puborectalis and anal region of the fetus and newborn.

The study was carried out in seven fetuses (ovulation ages were 16, 18, 20, 22, 26, 28, and 31 weeks, respectively) and in five full-term newborn babies. The modified Bielschowsky method and Barker's block silver impregnation were used. It was found that the muscle spindle was arranged in the puborectalis and the external sphincter muscles from the 20th week onward; the tendon organ was located in association with the musculo-tendinous junction of the puborectalis from the 20th week onward; the Pacinian corpuscle lay in the plane of cleavage between the internal anal sphincter and the external anal sphincter from the 22nd week onward, and in the presacral space from the 28th week onward, and the later lagged behind the former in development; the globular endings lay in the presacral space from the 28th week onward; and the free nerve ending was distributed in the epithelium of the anal mucosa and the epidermis around the anus from the 31st week onward. These sensory nerve endings tend to mature gradually with increasing age. It was concluded that these endings may be responsible for the reflex of the external anal sphincter and the anal sensation.

A comparison of three methods of assessing inter-observer variation applied to measurement of the symphysis-fundal height.

This study assesses the inter-observer variation of symphysis-fundal height measurements by three methods--the coefficient of variation, the correlation coefficient and the limits of agreement. The coefficient of variation was 4% and the correlation coefficient 0.959, yet the limits of agreement were very wide. Applying these limits to centile charts of symphysis-fundal height shows that the fundal height cannot be measured by different observers with sufficient agreement to separate small fundal heights from those which are not small, and this severely limits the usefulness of measurement of the symphysis-fundal height as a screening test for intrauterine growth retardation. We conclude that inter-observer variation should be assessed by the method of limits of agreement, and not by calculating the coefficient of variation or the correlation coefficient.

The symphysis pubis. Anatomic and pathologic considerations.

The symphysis pubis is a nonsynovial amphiarthrodial joint that is situated at the confluence of the two pubic bones. A thick intrapubic fibrocartilaginous disc is sandwiched between thin layers of hyaline cartilage. The inferior pubic ligament provides most of the joint's stability. Anatomic sections demonstrate a symphysis by the end of the second month of gestation. Thick cartilaginous end-plates are present at birth but become thin by the time of skeletal maturity. Congenital diseases resulting in failure of symphysis formation include exstrophy of the bladder and cleidocranial dysostosis. Both pyogenic and tuberculous infectious diseases involve the symphysis. Metabolic disease, such as renal osteodystrophy, produces widening, while ochronosis results in calcific deposits in the symphysis. Inflammatory disease, such as ankylosing spondylitis, results in bony fusion of the symphysis. Osteitis pubis, the most common inflammatory disease, is treated with anti-inflammatory medication and rest. Degenerative joint disease of the symphysis, which can cause groin pain, results from instability or from abnormal pelvic mechanics. As is the case with most joints, the symphysis serves as a barrier to tumor invasion. The patterns of trauma include diastasis, straddle fracture, intraarticular fracture and overlapping dislocation, and combinations of injuries.

The clinical value of measurements of the symphysis-fundus distance and ultrasonic measurements of the biparietal diameter in the diagnosis of intrauterine growth retardation.

The diagnostic efficiency in the prediction of intrauterine growth retardation (IUGR) of repeated measurements of the symphysis-fundus (SF) distance and repeated ultrasonic measurements of the biparietal diameter (BPD) was investigated in 377 pregnancies, all at risk for IUGR. Measurements of the SF distance were found to be more effective than ultrasonic BPD measurements for antenatal diagnosis of IUGR. For every correct diagnosis there were three false positive when using SF measurements and ten when using ultrasonic BPD measurements. When the SF method is used, repeated ultrasonic BPD measurements add very little information. The SF curve is a very simple and inexpensive method and should be used as a screening instrument for severe IUGR. When the SF curve is assessed as pathological, ultrasonic measurements also including other fetal dimensions than only BPD are recommended as a way of diagnosing IUGR.

[Multiplication of the different varieties of cells of the mouse pubic symphysis during growth and early gestation: radioautographic study with the use of tritiated thymidine]. / Multiplication des différentes variétés cellulaires de la symphyse pubienne de souris au cours de la croissance et de la première gestation : étude radioautographique à l'aide de la thymidine tritiée

1) A radioautographic study was undertaken after injection of tritiated thymidine during post-natal growth. The mitotic activity was localized in the three constituents of the mouse pubic symphysis: - in the osteogenic cartilage, labelled nuclei are numerous throughout animal growth; - in the articular cartilage, labelled nuclei are seldom encountered; - in the medial region, the chondroblasts, elongated dorso-ventrally, and the fibroblasts of the dorsal ligament show numerous labelled nuclei. 2. During the first pregnancy, the mitotic activity of the three constituents were examined separately: - in the osteogenic cartilage, the number of labelled cells increases at the beginning of the first pregnancy : the tibia epiphyseal cartilage apparently simultaneously shows revival of mitotic activity. After the 15th day of pregnancy, the osteogenic cartilage disappears by endochondral ossification; - in the articular cartilage and fibrocartilage, no mitotic activity is detectable as long as their typical characteristics are conserved. However, mititic activity becomes evident again when these cartilaginous cells cease to be surrounded by the typical chondroid matrix and become incorporated into the ligament. Cell multiplication therefore participated in symphyseal ligament dilatation.